Cannons can be found in Spyro the Dragon, Spyro 2: Ripto's Rage! and Spyro: Year of the Dragon in the Dragon Realms, Avalar and Forgotten Realms. They are used to shoot cannon balls at their target, which is usually out of reach or made of a material unbreakable by Spyro.
Soldiers were in charge of cannons in Peace Keepers. They would usually playfight eachother or attack Spyro with them.
A cannon could be found on the trolley on the Gear Grab Challenge in Breeze Harbor.
Blue cannons could be found all over Avalar and Forgotten Realms and were used to shoot for enemies and objects that were out of reach.
Wooden cannons could be hanging from balloons in Sorceress' Lair, to be shot down by Agent 9 for use by Spyro against her. This kind of cannon was free to move in all directions.